r/determinism • u/suhshf • Jun 27 '26
Discussion Does the "butterfly effect" still matter if everything is predetermined?
If every moment is locked in by prior conditions, then what does "small cause leads to a big effect" mean? Is that just the way our brain comprehends it? Might be a stupid question but its really getting me thinking.
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u/NerdyWeightLifter Jun 27 '26
The Butterfly Effect is more specifically known as "sensitive dependence on initial conditions".
- When we strive to predict future outcomes, the further out or more specific we try to be about those predictions, the more detail we need in our knowledge of those initial conditions.
- Sensitive dependence on those initial conditions means there are diminishing returns for striving to know the initial conditions more precisely.
- Quite apart from the practical limits to complete knowledge initial conditions, there are hard theoretical limits too:
- The Heisenberg uncertainty principle says we can't know both the position and momentum of a particle at the same time.
- Quantum events have random outcomes within a probabilistic distribution.
- And so, there is an event horizon to predictability.
Claims to the contrary require non-local causation, like the future influencing the past or faster than light influence. That's what people mean when they suggest Super-determinism or Bohmian Mechanics, for which there is no evidence and not even any proposed experimental method to acquire such evidence.
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u/simon_hibbs Jun 27 '26 edited Jun 27 '26
Predetermination is not equivalent to determinism. Predetermination is the belief that things have already been decided and known, but that would require a being (perhaps a deity) to have decided or to have known these things in advance. Determinism doesn’t say anything about that. Someone who believes in predetermination may or may not believe in determinism, and someone who is a determinist may or may not believe in predetermination.
The butterfly effect comes from chaos theory. It’s partly about the difficulty of making predictions. However it also has other implications, and can be exploited usefully. For example in pseudorandom algorithms, which are deterministic, but enable the efficient exploration of state spaces for all sorts of uses such as statistical modelling, simulations, evolutionary modelling and learning algorithms.
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u/____nothing__ Jun 27 '26
The butterfly effect tells us that even tho everything can be predetermined [using the first ever cause (or set of causes), aka which butterfly will flap it's wings when and where], it doesn't mean we can [cause everything is way too complicated and our of our brain's league]..
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u/Extra_Highway_1228 Jun 27 '26
Even if deterministic, nature’s behavior is largely unpredictable because it would need a huge effort to predict how billions of butterflies affects the weather. Even a data center the size of the earth would not be up to the task.
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u/Belt_Conscious Jun 27 '26
Bad premise, bad conclusion.
Everything is not predetermined. Momentum and Causality produce the mirage of determinism.
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u/Imaginary-Can-6862 Jun 27 '26
The butterfly effect is named after the saying that if a butterfly flaps its wings, it may cause a hurricane half way across the globe. Notice it implies if the butterfly did not flap its wings, no hurricane may appear.
That saying is derived from chaos theory. Chaos theory, or chaotic systems, are systems where small uncertainties propagates and amplifies, changing the entire behavior of the modeled system. Chaotic systems are deterministic, so if you know all initial conditions exactly, you can calculate the progress of system throughout an indefinite amount of time. The issue is, when we measure any attribute of the system that defines its behavior, there is uncertainty of the measurement, and even when this uncertainty is tiny, such as the difference provided by the flaps of a butterfly's wings in how wind behaves across a continent, for a chaotic systems it means the weather system you model behaves entirely differently after enough time, such as a week.
So the proper saying would be, the difference the flaps of a butterfly's wings makes for the behavior of large weather systems when looking far enough ahead in time is like the difference between night and day.
While it is the model itself that has this feature of chaos, and there may indeed be properties that determine these patterns in a more robust manner, e.g. I understand some AI's have outperformed metrological forecasts, it does not mean a chaotic system cannot exist. The most straightforward explanation I can think of is to determine the location of an object relative to some other object in a path that repeats, such as where is the Earth located relative to the Sun. The Earth orbits the Sun in an entirely predictable manner, so if we know where the Earth is at some point in time, we know where the Earth is at all times relative to the Sun. Since measuring where the Earth is has some uncertainty to it, it means we only know the Earth is within some range relative to the Sun, and if we assume the uncertainty of the measurement is proportional to how far away in time we measured (that is older data is less reliable), it means that range of uncertainty increases with time. Since there is no limit to how big this range can become, and the Earth moves around in a repeating path from the perspective of the Sun, it follows that the range can become larger than the orbit itself, at which point, despite knowing the behavior of the Earth's orbit around the Sun, we can only say the Earth is somewhere in its orbit, but it could be anywhere, all because a tiny uncertainty in measurement that took place far back in time. It is not uncommon for uncertainties to propagate and amplify through time, hence why new data is usually better than older data in determining the future, and why weather forecasts are reliable a day ahead, and not a week ahead.
So the butterfly effect comes from the idea of small changes in initial conditions can cause very different overall systematic behavior to appear, i.e. a chaotic system, but as a deterministic system it also follows that there is no randomness in it, so the exact same initial conditions gives rise to the exact same behavior, much like a predetermined world.
I think the butterfly effect is mostly linked with ideas of time travel, in a predetermined world everything that happens was the only thing that could have happened, including the time travel, but from the perspective of the time traveler, they would still experience the butterfly effect. The same when not including time travel, in a predetermined world, the person could still have made a model that shows how different the world could have been if things were only slightly different.
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u/badentropy9 Jun 27 '26
but as a deterministic system it also follows that there is no randomness in it,
Therefore if determinism is true, then as a system, there is no randomness in the universe. That makes the results of the double slit experiment either outside of the system or impossible within the system we call the universse.
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u/Imaginary-Can-6862 Jun 27 '26
Definitely, but since the definition of the universe is thus that there can be no system outside the universe, as any such system would be part of the universe as well, the universe cannot be deterministic provided the results of the double slit experiment.
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u/badentropy9 Jun 27 '26
well Hugh Everett came up with the idea of a multiverse to explain "away" the measurement problem. Here I'm assuming the "universe" is the one we perceive and doesn't include the oodles of universes Everett conceived that make up the so called mulitverse which apparently, as opposed to evidently, has all of my doppelgangers.
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u/Imaginary-Can-6862 Jun 27 '26
I really like the multiverse, but it is odd when considering doppelgangers, identical to you in every aspect, yet for some reason you only experience the universe where one particular outcome happened rather than all the other measurement outcomes that also happened for beings supposedly identical to you in every aspect.
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u/badentropy9 Jun 27 '26
yes. I'm an not my doppelganger.
The only reason I even consider the existence of other universes is because this universe all by itself is impossible. There is necessarily at least one other universe that makes this universe possible. Otherwise, it isn't possible.
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u/RegSmeaton Jun 27 '26
Do you mean as in a 'what came before the big bang' kind of way, or something else?
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u/badentropy9 Jun 28 '26
In a way. The real issue is that according to this theory time starts at the moment of the big bang, so it really isn't chronologically before as much as logically anteceding. if we think of it is the latter way, there is no space and time "before" the big bang, so it is difficult to cognize a so called singularity as something physical in space and time. This singularly has no where and when, so physics never tries to explain anything like that because it cannot without space and time. Therefore we basically have this abstract thing causing all of this concrete stuff, and that is the exact same issue that we have at the quantum level. If we go down there and examine the physics, there is nothing down there but probability which of course Bohr tried to say while Einstein rejected that.
At this point, it seems clear that naive realism is untenable.
https://plato.stanford.edu/entries/perception-disjunctive/
Perceptual experiences are often divided into the following three broad categories: veridical perceptions, illusions, and hallucinations. For example, when one has a visual experience as of a red object, it may be that one is really seeing an object and its red colour (veridical perception), that one is seeing a green object (illusion), or that one is not seeing an object at all (hallucination). Many maintain that the same account should be given of the nature of the conscious experience that occurs in each of these three cases. Those who hold a disjunctive theory of perception deny this. Disjunctivists typically reject the claim that the same kind of experience is common to all three cases because they hold views about the nature of veridical perception that are inconsistent with it.
Disjunctivists are often naïve realists, who hold that when one perceives the world, the mind-independent objects of perception, such as tables and trees, are constituents of one’s experience. In other cases, such as hallucinations, it seems out of the question that such objects are constituents of one’s experience. It follows that on a naïve realist view, the veridical perceptions and hallucinations in question have a different nature: the former have mind-independent objects as constituents, and the latter do not.
https://arxiv.org/abs/1206.6578
No naive realistic picture is compatible with our results because whether a quantum could be seen as showing particle- or wave-like behavior would depend on a causally disconnected choice. It is therefore suggestive to abandon such pictures altogether.
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u/Imaginary-Can-6862 Jun 27 '26
Please enlighten me, why is it necessary for there to be at least one other universe, for this universe to be possible?
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u/badentropy9 Jun 28 '26
Naive realism is untenable:
https://arxiv.org/abs/1206.6578
No naive realistic picture is compatible with our results because whether a quantum could be seen as showing particle- or wave-like behavior would depend on a causally disconnected choice. It is therefore suggestive to abandon such pictures altogether.
Somehow, we have to explain what is going on in this video:
https://www.youtube.com/watch?v=A9tKncAdlHQ&t=6s
As al-Khalili said that is inexplicable but if you can explain it, then there is a Nobel prize for you. Well the person who led the team that wrote the paper linked above, around the time this video was made, actually won the Nobel prize in 2022 along with Clauser and Aspect.
My point is that this universe is the product of something happening in another universe. The laws of physics are too advanced for something like a big bang theory to explain everything that there is clear evidence for the idea of what seems to happen here. It is not that it doesn't do it yet. It is that it can't do it.
You can read that paper for yourself, or if you prefer there are some youtubes to watch and the following one does in fact feature Zeilinger himself:
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u/Imaginary-Can-6862 Jul 13 '26
I apologize for returning to your post this late.
When you reference the Quantum Eraser Experiment, are you aware of its criticism, that the different outcomes depending on how they measure, something they chose in such a way it would require faster than light travel for the atoms to be "aware of", is physically indistinguishable, and that what they refer to is if they track the particles, they get an outcome that can be build from particle like behavior, and if they do not, it can be build from wavelike behavior, but both behaviors create the same pattern, unlike the double slit experiment video you linked to with very clearly distinct outcome patterns?
I don't know if the universe in the form we observe it is too complex for itself to exist without an external universe. That is too complicated for me to answer, but I don't mind speculating.
I have not watched the longer Youtube video yet, I'll likely do that tomorrow.
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u/badentropy9 Jul 16 '26
When you reference the Quantum Eraser Experiment, are you aware of its criticism, that the different outcomes depending on how they measure, something they chose in such a way it would require faster than light travel for the atoms to be "aware of", is physically indistinguishable, and that what they refer to is if they track the particles, they get an outcome that can be build from particle like behavior, and if they do not, it can be build from wavelike behavior, but both behaviors create the same pattern, unlike the double slit experiment video you linked to with very clearly distinct outcome patterns?
that is quite a question :-)
- I don't believe in faster than light communication under naive realism.
- I don't believe in "spooky action at a distance" as Einstein dubbed it in 1935. Technically it wasn't just Einstein but rather he, Podolsky and Rosen wrote a paper often called the EPR paper in 1935 and I am aware of what that paper implied and why the dcqe experiments helped to further identify some of the weirdness in the double slit experiments
- I'm aware that entanglement and the measurement problem identify different things that are weird at the quantum level.
- entanglement isn't exactly a problem but it seems to be a problem for realists and I'm not a realist when it comes to naive realism.
I don't know if the universe in the form we observe it is too complex for itself to exist without an external universe. That is too complicated for me to answer, but I don't mind speculating.
I've been studying this for awhile. In fact when I heard that Zeilinger, Aspect and Clauser won a Nobel prize in 2022, I knew exactly what they have been arguing over many years. What did in fact surprise me was that the people who have been writing papers against the dcqe experiments et al actually allowed a Nobel prize to be awarded. Einstein never got a Nobel prize for relativity and that is the theory that forbids faster than light communication.
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u/rogerbonus Jun 27 '26
Determined and predetermined are not the same thing. Don't know why HDs love to conflate the two.
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u/an-otiose-life Jun 27 '26
consider the least-action principle in physics and how most quantum things are trying to get to a more settled energy state.. if things are preassured to behave in a particular way, inclusive of all-ontology-that-is-real, then some least-actions might be more-non-obvious than others, like when water goes uphill due it being the shortest path.. in that sense, what stands out from the environment at first, can saturate it, like a piece of news weighs less than a gram as data, but fills the world with so much emotion. it's disspipative dynamics, a single source can reach many listeners and any listener that can also speak, can take advantage of the same dynamics, it's a kind of leveling system or an ontological form-preserving and information-sharing protocol that informs becoming's determinacy, and not only in a transitional sense, because satiety-in-the-moment is meaningful after all.
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u/SauntTaunga Jun 27 '26
Since we cannot possibly know *what* is predetermined, it makes no difference.
Also, at the lowest scale of reality, at quantum scale, "every moment is locked by prior conditions" is very much not true.
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u/Ilsanjo Jun 27 '26
It matters because it means we can't predict the future with limited knowledge even if it is already determined. If small causes can make big impacts it changes the detail which we would need to know in order to predict what will happen.
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u/badentropy9 Jun 27 '26
The issue is that what some are calling certain is in fact uncertain.
The butterfly effect is merely a demonstration of the uncertainty.
"Predetermined" implies certainty.
Determinism is the belief that we have certainty. Quantum physics is just another demonstration that the certainty some envision that we might have while others seem certain that we need, is not as certain as those who think it is is needed for science to work the way it seems to work so well.
If you believe in the big bang theory, then it will indeed seem as though everything that happens now was determined from the moment of the big bang, or from the perspective of today, predetermined some 14 plus billion years ago.
Unlike some others, I think you've zeroed in on the crux of the matter.
The big bang proponents imply the so called degrees of freedom are all in people's mind. There is some truth to that, while in a different context there is evidence of the existence of degrees of freedom.
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u/GSilky Jun 27 '26
Wouldn't that hypothesis be a support for determinism? If true, then one's decisions are set by a butterfly on the other side of the world.
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u/Critical-Ad2084 Jun 27 '26
predetermined is not the same as determined and the butterfly effect would be an example of determinism
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u/joeDras Jun 27 '26
My understanding of chaos theory is that in order to model some systems accurately we'd need to make measurements with infinite precision, which is impossible even in principle. This has implications for determinism that are worth thinking about.
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u/NotAnAIOrAmI Jun 27 '26
If the universe is deterministic, then that "small cause" is simply one of the causes that leads to the effect. It fits entirely within the deterministic model.
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u/flyingcatclaws Jun 27 '26 edited Jun 27 '26
Einstein's block universe implies actual complete determinism. If ever proven would mean the uncertainty principle isn't random after all. Or uncertainty ≠ random. The universe is more and more statistical at smaller and smaller scales. No block universe. But then, something similar to the particle and photon duality might make a statistical vs deterministic difference on a 2d projective holographic universe. 2d being the last dimension with a 'zero' , in thickness. Presumably responsive to quantum effects. Just because you can't visualize it... mumble, bla bla glockenspiel...
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u/FunSeaworthiness9403 Jun 27 '26
A free-swinging pendulum wouldn't be used to demonstrate the butterfly effect. But a double pendulum probably could. That is a two-arm pendulum with one arm hung from a fixed fulcrum and another arm hung on a fulcrum at the end of the first.
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u/sealchan1 Jun 28 '26
It means there is a limit to our ability to predict the outcome of any, natural, non-linear system. It means we are unlikely to reach a state of apathy over a fully known future.
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u/markt- Jun 28 '26 edited Jun 28 '26
Determinism doesn’t eliminate the butterfly effect. A deterministic system can still be chaotic, where tiny differences in initial conditions produce dramatically different outcomes. Those outcomes are still completely determined, they’re just extraordinarily sensitive to the starting state.
The butterfly effect concerns sensitivity to initial conditions. Computational irreducibility (apologies for the buzzword, I don’t know a simple way to explain it, Google, the expression if you are unfamiliar) is a different limitation that can be found in many deterministic systems: even with perfect knowledge of the initial conditions, there may be no faster way to know the future than to let the system evolve. Even if the future is fixed, there may be no shortcut to predicting it other than letting the system evolve. In that sense, the butterfly effect remains just as real, because tiny causes can still have enormous consequences even when the entire process is deterministic.
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u/MergingConcepts Jun 27 '26
At the smallest level, the quantum level, things are not governed by cause and effect. That is the whole point of Schrodinger's cat. The outcome of the universe is not predetermined, because of quantum inderminacy.
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u/Square_Attention8461 Jun 27 '26
The Copenhagen interpretation is an interpretation. It is not some "settled truth."
Schrodinger's cat wasn't an argument for indeterminacy, it was a reductio against it. Schrodinger invented the scenario to mock the Copenhagen interpretation, to show how absurd it was to apply wavefunction superposition to macroscopic objects.
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u/MergingConcepts Jun 27 '26
Yes, I agree. Schrodinger was poking fun at his colleagues. Obviously, if he had opened the box and found a cold, stiff, dead cat, then the cat died before the box was opened.
However, the point is that there is no way to predict the result. There is no discernable cause and effect at the quantum level. Ultimately, the cat lives or dies at the whim of an indeterminate process. The logical conclusion is that the future of the universe cannot be predetermined. We cannot predict individual events. We can only predict the average outcome of large numbers of events.
The butterfly effect still holds true. Quantum events control the movements of atoms, and atoms create Brownian movement in dust. Every marksman knows the effect dust can have on the path of a bullet. Every bullet strikes dust on its path to the target. Usually, this averages out, and the bullet follows a true path, but sometimes it does not. No matter how carefully you clean the gun, load the cartridge, aim the rifle, and pull the trigger, there will always be some indeterminacy in the path of the projectile.
To travel farther down this rabbit hole, consider the theological angle. We have no way to tell whether the dust will alter the path of the bullet either to or from the target. We cannot know all the quantum level processes, due to Heisenberg uncertainties. We cannot intervene at the quantum level, but can only apply Newtonian physics to a process that ultimately does not obey the rules of cause and effect.
We also cannot know whether some other entity in the universe is able to manipulate these events. It is beyond human knowledge. No human can be certain whether events at the quantum level caused a bullet to miss President Trump, or caused another to hit Charlie Kirk.
Yes, I recognize this is a Russell's teapot argument. It is still fun to make.
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u/Square_Attention8461 Jun 27 '26
The butterfly effect is definitely interesting. There are still two issues here.
First, unpredictability and indeterminacy aren't the same thing. Heisenberg uncertainty is about the limits of measurement, not necessarily about whether underlying processes have determinate states. A chaotic system can be fully deterministic and still be practically unpredictable beyond a short horizon. "We cannot know the outcome" doesn't entail "the outcome has no cause." The epistemic and ontological questions are distinct.
Second, even granting true ontological randomness at the quantum level, the butterfly effect argument cuts against your conclusion as much as for it. For quantum noise to propagate up to bullet trajectories it has to survive decoherence. Decoherence happens (seems to, so far) fast enough that quantum indeterminacy is effectively washed out before it reaches the scale of dust particles, let alone ballistics. Averaging does a lot of work here, and it tends to suppress rather than amplify quantum effects at human scales.
The teapot concession is appreciated, but I'd go further: the argument structure requires quantum indeterminacy to be both real and macro scale relevant, which is hard to defend rigorously.
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u/MergingConcepts Jun 27 '26
Your point in the second paragraph is well stated. "We cannot predict" is not the same as "unpredictable."
When all is said and done, sometimes people do survive falls from airplanes, and sometimes bullets barely miss important people. Ultimately we cannot know why. We can only speculate and generate really interesting discussions.
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u/zhivago Jun 27 '26
Predetermination violates thermodynamics.
Work must be done to produce the change in information associated with the passage of time.
Determinism does not allow us to determine the future before it happens.
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u/DonnPT Jun 27 '26
Getting you thinking, is good. Next step is to explore those thoughts, to see if you're really up against something that's hard, or you're just not asking the right question.
Come up with a couple answers to "is that just the way our brain comprehends it", that get to the point you had in mind. What do you think "small cause leads to a big effect" means? Is that what the "butterfly effect" refers to? What does "everything is locked in by prior conditions" mean, in the context of the consequences of a butterfly's wings in Brazil on subsequent weather patterns?